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Full text of "Metallurgy Of Cast Iron"

CHAPTER XXVI.
ORIGIN   AND    UTILITY   OF   STANDARDIZED DRILLINGS.
To test the practicability of obtaining uniform analyses of one quarter piece of pig iron, samples of well mixed pig drillings were sent out by the author, during the summer of 1897, to twenty leading chemists in different parts of the country to be analyzed, with a view of ascertaining how closely their results would agree. The reports were such as were anticipated. No two were alike, and the difference between the extremes was so great that a founder being guided by one extreme, in forming a comparative measure for making mixtures, could, should he accept the other, sustain great losses, "-or obtain a grade of metal far different than what should exist in his castings. The evil results obtained from such variations of analysis were such as to prevent chemistry ever being universally established in founding. Exhibiting the weakness of chemical methods, as did the author by the publication of the reports obtained, caused another party to send out samples of drillings to fifty chemists with the view of getting better results. No. i of Table 27 shows the difference in the greatest variations of the analyses reported to the author, and No. 2 shows the greatest variation in the analyses obtained by the second party:equire to be a much more radical difference in the grain of two furnace casts, of like analyses in the same brand, than is shown by the samples Nos. I and 2, Fig. 43. The difference that a very open and very close grained iron of the same analyses and brand could make would be in the most close grained iron giving a slightly softer casting than the open iron, after the principles presented in Chapter 47, pages 337 to 339. However, there is no reason why any one should make it a point to insist on accepting only open or close grained iron in connection with exacting any certain specified analyses from blast furnaces, as the slight difference possible in the most radical cases of open and close grained iron can be regulated by a slight variation in silicon when making a mixture, and which anyone can easily do, if they so desire,  "